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Biomedical subjects

Ujjwal K Chowdhury

Publications and source records attributed to Ujjwal K Chowdhury.

At least 19 recordsLinked to original sources
PubMed2006

Intra-aortic balloon counterpulsation in a patient with the failing Fontan circulation.

We report a 23-year-old patient undergoing functionally univentricular repair who developed cardiac failure due primarily to systemic ventricular dysfunction. The failing Fontan circulation was successfully re-established using intra-aortic balloon counterpulsation. Aortic counterpulsation facilitates recovery of systemic ventricular function, and appears to be a reasonable alternative in select instances of cardiac failure in patients with the Fontan circulation.

Adult↗
PubMed2006

Serial radionuclide angiographic assessment of left ventricular ejection fraction and regional wall motion after mitral valve replacement in patients with rheumatic disease.

BACKGROUND: This study was designed to prospectively investigate the effects of total or partial chordal-sparing and chordal-nonsparing mitral valve replacement (MVR) procedures on regional and global ventricular function in a rheumatic population using sequential multiple-gated acquisition scan. METHODS: One hundred five consecutive patients undergoing different techniques of chordal preservation procedures during MVR are included in this prospective study. Fifteen patients had complete excision of the chordopapillary apparatus (group 1), 34 had total chordal preservation (group 2), and 56 had preservation of the posterior chordopapillary apparatus (group 3). Radionuclide-derived left ventricular ejection fraction (LVEF) and regional wall motion (RWM) studies on 99 survivors were performed preoperatively, at discharge, at 1 year, and at 2 years. RESULTS: At discharge, there was a decline in LVEF in all the 3 groups. Statistically significant improvement in ejection fraction occurred in the chordal preservation groups (2 and 3) (P < .05) as compared with the nonchordal group immediately and late postoperatively. Only the total chordal group (2) demonstrated complete recovery of LVEF by 2 years postoperatively. Significant and persistent RWM abnormalities were noted in both the nonchordal and posterior chordal groups. CONCLUSIONS: We conclude that complete retention of the chordopapillary apparatus during MVR provides superior results compared with nonchordal and partial chordal preservation in terms of preservation of LVEF and reduced incidence of abnormal postoperative RWM.

Adult↗
PubMed2006

Pericardiectomy for constrictive pericarditis: a clinical, echocardiographic, and hemodynamic evaluation of two surgical techniques.

BACKGROUND: This study was designed to compare the outcomes after total versus partial pericardiectomy clinically, echocardiographically, and hemodynamically. METHODS: Three hundred ninety-five patients undergoing pericardiectomy for constrictive pericarditis between January 1985 and December 2004 were studied. Age was 10 months to 71 years (mean, 25.1 +/- 13.4 years). Three hundred thirty-eight patients (85.6%) underwent total pericardiectomy (group I), and 57 patients (14.4%) underwent partial pericardiectomy (group II). RESULTS: Operative and late mortality rates were 7.6% and 4.9%, respectively. Preoperative high right atrial pressure, hyperbilirubinemia, renal dysfunction, atrial fibrillation, pericardial calcification, thoracotomy approach, and partial pericardiectomy were significant risk factors for death. The risk of death was 4.5 times higher (95% confidence interval: 2.05 to 9.75) in patients undergoing partial pericardiectomy. At a mean follow-up of 17.9 +/- 0.3 years (95% confidence interval: 17.3 to 18.6), actuarial survival was 83.8% +/- 0.04% in group I and 73.9% +/- 0.06% in group II (p = 0.004). At their last follow-up, 96.3% survivors of group I and 79.1% survivors of group II were in New York Heart Association class I/II (p < 0.001). CONCLUSIONS: Total pericardiectomy is associated with lower perioperative and late mortality, and confers significant long-term advantage by providing superior hemodynamics that appear to be independent of the etiology of constrictive pericarditis.

Adolescent↗
PubMed2006

Noninvasive assessment of repaired tetralogy of Fallot by magnetic resonance imaging and dynamic radionuclide studies.

BACKGROUND: This study was designed to validate the diagnostic accuracy of magnetic resonance imaging (MRI) in evaluating biventricular ejection fraction and to quantify pulmonary regurgitant fraction (PRF) in patients after repair of tetralogy of Fallot. METHODS: Two hundred and eighty survivors of repaired tetralogy of Fallot aged 42 months to 40 years (mean, 142.2 +/- 85.3 months) underwent cardiac MRI, first-pass and gated radionuclide ventriculography (RNV) for the assessment of biventricular function, and PRF after 89.26 +/- 42.40 months. The receiver operating characteristic curve analysis was done to quantify the diagnostic accuracy of MRI. RESULTS: There was statistically significant agreement between MRI and RNV in evaluating right and left ventricular function. An MRI-derived right ventricular ejection fraction 47.2% or greater than normal was associated with a sensitivity of 92.3% and a specificity of 92.3%. An MRI-derived left ventricular ejection fraction 53.9% or greater than normal was associated with a sensitivity of 93.2% and a specificity of 93.3%. Area analysis indicated that 97.34% (standard error [SE] = 0.0118) and 98.56% (SE = 0.0052) of the time values of right and left ventricular ejection fraction were higher for patients with normal right and left ventricular functions, respectively, compared with abnormal. There was a strong agreement between velocity-encoded and stroke volume-derived PRF [(r = 0.886, p < 0.001; d = 2.62 +/- 1.12, p < 0.0001; r' = 0.121, p = 0.051; b = 0.96 (SE = 0.012); p < 0.0001; ICC = 0.98, p < 0.0001). Higher PRF was associated with increased indexed right ventricular dimensions and inversely correlated with biventricular ejection fractions. CONCLUSIONS: The MRI-derived ejection fraction values predictably separate patients with normal ventricular function from abnormal. Velocity-encoded MRI can accurately quantitate PRF in tetralogy of Fallot.

Adolescent↗
PubMed2006

Histopathology of the right ventricular outflow tract and its relationship to clinical outcomes and arrhythmias in patients with tetralogy of Fallot.

OBJECTIVES: The purposes of this study were to evaluate the myocardial histopathology and ultrastructure in patients with tetralogy of Fallot and to identify the histopathologic characteristics that may predispose patients to postoperative myocardial dysfunction and arrhythmias. PATIENTS AND METHODS: Operatively resected crista supraventricularis muscle from 183 patients undergoing intracardiac repair of tetralogy of Fallot aged 12 months to 42 years (mean, 106.84 +/- 79.35 months) were studied by light and electron microscopy. Biventricular function and cardiac rhythm were assessed by 2-dimensional echocardiography and electrocardiography. RESULTS: The incidence of moderate or severe cellular hypertrophy, endocardial thickening, and interstitial fibrosis was 36%, 68.3%, and 65%, respectively. Logistic regression analysis demonstrated age greater than 4 years, systemic arterial desaturation, higher hematocrit values, and elevated ventricular end-diastolic pressures as the major predisposing risk factors for pathologic changes. Twenty-seven (81.8%) patients more than 15 years of age and 29 (29.3%) patients between 4 and 15 years of age had predominant right ventricular dysfunction and low cardiac output (chi(2) [1 degree of freedom (df)] = 27.95; P < .001; odds ratio [OR] = 10.86 [3.75-33.10]). Ventricular arrhythmia was detected in 11 patients in whom repair was performed between 4 and 15 years of age and in 13 patients whose age at operation was 15 years or older. According to an additive logistic model, the effect of age at repair on the influence of ventricular arrhythmia was significant (chi(2) [1 df] = 24.4; P < .001; OR = 8.21 (2.96-23.11]). CONCLUSIONS: The great majority of myocardial tissues in cyanotic tetralogy of Fallot indicates pre-existing ultrastructural hypertrophic and degenerative changes. The changes are more pronounced in older patients subjected to long-standing cyanosis and pressure overload and may account for or may coexist with the higher incidence of myocardial dysfunction and ventricular arrhythmia.

Adolescent↗
PubMed2006

Criterions for selection of patients for, and results of, a new technique for construction of the modified Blalock-Taussig shunt.

BACKGROUND: We describe alternative surgical techniques for construction of systemic-to-pulmonary arterial shunts, and propose criterions for their application in selected patients. PATIENTS AND METHODS: We constructed a variety of modified systemic-to-pulmonary arterial shunts, using polytetrafluoroethylene grafts, in 92 selected patients with cyanotic congenital heart disease and anomalies of the aortic arch and systemic veins. Their age ranged from 7 days to 3.6 years, with a mean of 7.08 months. We performed 88 operations through a thoracotomy. Of this cohort, 60 patients underwent a second-stage operation, with 15 receiving a superior cavopulmonary connection, 16 a total cavopulmonary connection, and 29 proceeding to biventricular repair after a mean interval of 15.6 months. We have 21 patients awaiting their second or final stage of palliation. RESULTS: There were five early (5.4%) and six late deaths (6.8%), two of which were related to construction of the shunts. At a mean follow-up of 45.29 months, the increase in diameter of pulmonary trunk and its right and left branches was uniform and significant (p value less than 0.001). Pulmonary arterial distortion requiring correction at the time of second-stage operation was observed in 5 patients (6.1%). Adequate overall palliation was achieved in 98% of the cohort at 8 months, 91% at 12 months, and 58% at 18 months. CONCLUSIONS: Patients with a right- or left-sided aortic arch and right-sided descending thoracic aorta, those with anomalies of systemic venous drainage masking the origin of great arterial branches, and those with disproportionately small subclavian arteries, constitute the ideal candidates for our suggested modification of the construction of a modified Blalock-Taussig shunt. The palliation provided by these shunts was satisfactory, with predictable growth of pulmonary arteries, insignificant distortion in the great majority, and easy take-down.

Anastomosis, Surgical↗
PubMed2006

Myocardial injury in coronary artery bypass grafting: On-pump versus off-pump comparison by measuring heart-type fatty-acid-binding protein release.

This prospective study uses heart-type fatty-acid-binding protein (hFABP) and creatine kinase-MB (CK-MB) release to compare myocardial injury in on-pump versus off-pump coronary artery bypass grafting (CABG). Fifty patients were randomly assigned to on-pump or off-pump CABG. The hFABP and CK-MB concentrations were measured in serial venous blood samples drawn before heparinization in both groups and after aortic unclamping at 1, 2, 4, 8, 24, 48, and 72 hours in the on-pump group. In the off-pump group, samples were taken after the last distal anastomosis at the same time intervals as in the on-pump group. The total amount of hFABP and CK-MB released was significantly higher in the on-pump than in the off-pump group (hFABP = 100.43 +/- 77.63 vs 3.94 +/- 0.36 ng/mL, P < 0.0001; CK-MB = 33.33 +/- 3.81 vs 28.65 +/- 3.91 log units, P < 0.001). In all patients, hFABP levels peaked as early as 1 hour after declamping (on-pump group) or 2 hours after the last distal anastomosis (off-pump group), whereas CK-MB peaked only at 4 hours after declamping (on-pump group) or 24 hours after the last distal anastomosis (off-pump group). The lower release of hFABP and CK-MB in the off-pump CABG group indicates that on-pump CABG with cardioplegic arrest causes more myocardial damage than does off-pump CABG. Heart-type fatty-acid-binding protein is a more rapid marker of perioperative myocardial damage, peaks earlier than CK-MB, and may predict the requirement for intensive monitoring for postoperative myocardial infarction.

Aged↗
PubMed2005

Right pulmonary artery to left atrium communication.

This is a collective review of 59 published cases of right pulmonary artery to left atrium communication in the English-language literature. In this article, we review the literature on the clinical presentation, anatomic variations, diagnostic features, and management considerations of previously reported cases. Two-dimensional echocardiography and cardiac catheterization including selective angiography provided the necessary diagnostic information and defined the anatomy before surgery in all patients. Various management options including medical, surgical, and transcatheter closure have been reported. The lesions have been classified into four types (I, II, III, and IV) that have a bearing on the appropriate surgical approach and techniques of repair that are discussed in the text. Use of extracorporeal circulation may be considered in selected instances. The operative mortality rate during the earlier era (1950 to 1979) was high, at 22%. More recently, the mortality rate has approached zero. An individualized surgical approach depending on the type of surgical connections is recommended.

Adolescent↗
PubMed2005

Mitral valve replacement with and without chordal preservation in a rheumatic population: serial echocardiographic assessment of left ventricular size and function.

BACKGROUND: The aim of this study is to investigate the feasibility of chordal-sparing mitral valve replacement procedures in a rheumatic population, and to determine the early and late effects of different chordal preservation procedures on the clinical outcome and left ventricular mechanics. METHODS: Various techniques of chordal preservation during mitral valve replacement for rheumatic heart disease in 451 patients between 1996 and 1999 are described. The mean age was 35.6 +/- 19.0 years (range, 15 to 55 years). Seventy patients had complete excision of the subvalvular apparatus (group I), 124 had preservation of the posterior chordopapillary apparatus (group II), and 257 had total chordal preservation (group III). Echocardiography was performed preoperatively, at discharge, at 1 year, and at 4 years. RESULTS: Chordal preservation groups (II and III) demonstrated significant improvement (p < 0.05) in left ventricular function immediately and late postoperatively. Reduction of left ventricular end-systolic and end-diastolic volume was significant in the chordal preservation groups (II and III) as compared to the nonchordal group (group I; p < 0.005). The total chordal group demonstrated greater fractional change of left ventricular end-systolic volume as compared to the posterior chordal and nonchordal group. The left ventricular ejection fraction and fractional shortening continued to decline over time in the nonchordal cohort (p = 0.05 and p = 0.001, respectively) and did not improve by 4 years. Statistically significant change in ejection fraction occurred in the chordal preservation groups as compared to the nonchordal group. CONCLUSIONS: We conclude that total chordal preservation is possible in the large majority of rheumatic patients and confers significant long-term advantage by preserving left ventricular function. The surgical technique should be individualized.

Adult↗
PubMed2005

Specific issues after extracardiac fontan operation: ventricular function, growth potential, arrhythmia, and thromboembolism.

BACKGROUND: The purpose of this study was to define the prevalence of specific sequelae after extracardiac Fontan operation. METHODS: Sixty-five consecutive patients undergoing extracardiac Fontan operation were studied for mortality, Fontan failure, systemic ventricular function, supraventricular arrhythmias, thromboembolism, and growth potential. Age was 3 to 31 years (mean +/- standard deviation, 9.4 +/- 1.8; median, 7 years). The conduits were constructed of polytetrafluoroethylene (n = 50), and "viable" in situ pericardium (n = 15). The patients underwent serial echocardiogram, dynamic radionuclide studies, and cardiac catheterization. RESULTS: Operative mortality was 3%, and the incidence of conduit thrombosis was 4.6%. There was paradoxic filling of the right lung after femoral injection of the radiotracer in all cases of conduit obstruction. Perioperative and late postoperative supraventricular arrhythmias were observed in 9.2% and 4.7% of patients, respectively. Risk factors for supraventricular arrhythmias included systemic ventricular dysfunction (p = 0.000), heterotaxy syndrome (p = 0.008), systemic venous anomalies (p = 0.015), and previous bidirectional Glenn operation (p = 0.017). At a mean follow-up of 77 +/- 2 months (range, 8 to 79 months), there were no late deaths (actuarial survival at 79 months, 96.9% +/- 0.02%). Serial echocardiograms demonstrated evidence of growth of the viable tunnels. Postoperatively, there was transient depression of ejection fraction in all patients (p = 0.000). CONCLUSIONS: Supraventricular arrhythmias after extracardiac Fontan are more common in patients with heterotaxy syndrome, bilateral superior venae cavae, systemic ventricular dysfunction, and those undergoing completion Fontan operation. The viable tunnel may emerge as an optimal alternative by virtue of reduction of supraventricular arrhythmias, elimination of the need for anticoagulation, and addressing the issue of growth potential in selected patients.

Adolescent↗
PubMed2005

One and one-half ventricle repair: results and concerns.

BACKGROUND: The study was designed to assess the long-term results of one and one-half ventricular repair on systemic and pulmonary circulation, right ventricular growth and function, and the prevalence of arrhythmias. METHODS: Eighty-four patients undergoing one and one-half ventricular repair between January 1990 and December 2003 were studied. Age was 4 to 504 months (mean, 47.9 +/- 57.3 months). Sixty-nine survivors underwent serial echocardiography, radionuclide studies, cardiac magnetic resonance imaging, and cardiac catheterization. RESULTS: Operative and late mortality were 10.7% and 8%, respectively. Perioperative and postoperative supraventricular arrhythmias were observed in 14.3% and 15.9% of patients, respectively. Risk factors for supraventricular arrhythmias included systemic ventricular dysfunction, heterotaxy syndrome, and Ebstein's anomaly. Mean late postoperative superior vena caval pressure was 14.2 +/- 1.52 mm Hg and right atrial pressure was 6.6 +/- 0.74 mm Hg. At a median follow-up of 87 months, actuarial survival was 81.9% +/- 0.04%, and 89.8% were in New York Heart Association class I or II. Serial cine-magnetic resonance imaging demonstrated significant growth of tricuspid valve and right ventricular cavity in 45% of patients. CONCLUSIONS: One and one-half ventricular repair can be performed with an acceptable risk. The operation maintains a low pressure in the inferior vena caval tributaries, and reverses the Fontan paradox. Patients with tripartite right ventricles demonstrated a tendency toward enlargement of the pulmonary ventricular chamber commensurable with somatic growth.

Adolescent↗
PubMed2005

Twenty-eight-year survival of stent-mounted aortic homograft in the mitral position: case report.

The case is presented of a long-term survivor after bioprosthetic valve implantation. A stent-mounted aortic homograft had been implanted in the mitral position, and survived for 28 years before being removed due to a tear in the base of leaflet, resulting in mitral regurgitation. The technique was discontinued in the mid- 1970s following reports of detachment of aortic valve cusps from the stent. The current case report may rekindle interest in the method, and also lead to an investigation of the factors that influence structural deterioration of bioprosthetic valves.

Aortic Valve↗
PubMed2004

Postoperative assessment of the univentricular repair by dynamic radionuclide studies.

BACKGROUND: The purpose of this investigation was to determine the role of radionuclide studies in evaluating postoperative Fontan hemodynamics and to quantify its diagnostic accuracy. METHODS: One hundred five patients (105), aged 11 months to 35 years old, who had undergone univentricular repair, underwent first-pass and multigated acquisition scan 1 month to 10 years after univentricular repair. Forty-five patients with evidence of Fontan failure underwent radionuclide studies using Technetium-99 m as well as cardiac catheterization (group 1). The remaining sixty randomly selected patients with excellent functional status received radionuclide studies alone (group 2). The receiver operating characteristic curve analysis was done to quantify the diagnostic accuracy of the first-pass study. RESULTS: There was paradoxical filling of the right lung after femoral injection in all cases of tunnel or conduit obstruction. A first-pass transit time of 16 to 25 seconds (mean +/- standard deviation [SD] = 18.82 +/- 2.69) was always associated with Fontan failure and high right atrial pressure (range = 20 to 24 mm Hg, mean +/- SD = 22.02 +/- 1.58). A first-pass transit time of 16 seconds was associated with a sensitivity of 100% and a specificity of 93.33%. The predictive accuracy of a positive or negative result was 91.8% and 100% respectively. The area measured under the receiver operating characteristic curve indicates that 99.41% (SE +/- 0.0035) of the time, the value of first-pass time is higher for the Fontan failure group (group 1) compared to the normal group (group 2; p = 0.000). CONCLUSIONS: Our data indicate that Fontan circuit can be reliably evaluated for both anatomic and functional flaws by radionuclide studies; radionuclide first-pass time may be used to predict the chances of Fontan failure postoperatively as well as its presence; and in the presence of atrial fibrillation with fast ventricular rate, analysis using first-pass radionuclide may be impossible and gated equilibrium radionuclide angiocardiography may be the preferred method. Inspection of the systemic ventricular time-activity curve is of crucial importance in this regard.

Adolescent↗
PubMed2004

Histopathology and morphometry of radial artery conduits: basic study and clinical application.

BACKGROUND: The purpose of this study was to determine the pathohistology, morphometry, and risk factors for the development of intimal hyperplasia, calcification, and arteriosclerosis in the radial artery and to compare the morphometry of the distal and proximal radial arteries. METHODS: A total of 190 proximal and distal radial artery specimens obtained from patients who underwent myocardial revascularization were exposed to histopathologic and morphometric analysis. The severity of disease was evaluated on the basis of the percentage of luminal narrowing, intimal thickness index, and intima-to-media ratio. RESULTS: Sixty-two proximal (32.6%) and 22 distal (11.5%) radial artery segments were indicated as histologically normal. Morphometric analysis (Z test) revealed a lesser degree of intimal hyperplasia and luminal narrowing in the proximal segments compared with the distal segments (p < 0.001). The incidence of intimal hyperplasia, medial calcification, and arteriosclerosis in the distal radial arteries was 76.3%, 6.3%, and 5.78%, respectively. Using multivariate logistic regression, we have identified three significant predictors for intimal hyperplasia. Expressed as an odds ratio with a 95% confidence interval, these included (i) age greater than 50 years (1.052; 1.000-1.106, p = 0.052), (ii) smoking (14.073; 5.293-37.414, p = 0.000), and (iii) hypertension (2.777; 1.171-6.583, p = 0.020). Factors associated with an increased likelihood of medial calcification and arteriosclerosis included a history of smoking, diabetes, hypercholesterolemia, peripheral arterial disease, and chronic renal failure (p < 0.05). CONCLUSIONS: The great majority of radial artery conduits indicate preexisting intimal hyperplasia mostly affecting the distal portion. Therefore in cases of longer diseased segments of radial arteries, the discarded segments should be the distal end. Care should be taken when selecting radial artery as a conduit in myocardial revascularization, particularly in elderly males, diabetics, smokers, hypertensive patients, and in those with associated peripheral vascular disease.

Adult↗
PubMed2004

Viable extracardiac total right heart bypass: technical considerations and mid-term results.

BACKGROUND: Direct connection of both caval veins to the pulmonary arterial system would be the ideal right heart bypass by virtue of elimination of prosthetic material and extensive atrial suture lines. However, it can be applied only to selected patients with peculiar anatomical arrangements. We decided to perform total extracardiac right heart bypass using pedicled in situ pericardium in situations when a direct connection was not possible. METHODS: A cohort of five patients, aged 3.5, 4, 10, 10 and 31 years, respectively, with complex cyanotic congenital heart diseases were candidated to extracardiac total cavopulmonary connection using viable in situ pericardium. Aortic cross-clamp was completely avoided in all patients. RESULTS: There was no early or late death. Postoperatively, all patients are in functional class I and in normal sinus rhythm at a mean follow-up of 30 months (S.D.=+/-19 months). Postoperative serial echocardiograms revealed wide, unrestricted anastomoses, unobstructed venous flow to both pulmonary arteries with cardiac pulsations and respiratory variations in the pulmonary arteries due to compressible lateral tunnel. Cavopulmonary angiograms (n=5) in late postoperative period have demonstrated a smooth, nonturbulent, somewhat pulsatile flow without pressure gradient. CONCLUSIONS: The technical advantages and haemodynamic benefits of this operation are encouraging. A longer follow-up is needed to confirm the early results, especially late atrial dysrrhythmias, pulmonary venous obstruction, thromboembolic complications and growth of the conduit.

Journal Article↗
PubMed2002

Alternative approach for angioplasty of stenosed left pulmonary artery following intracardiac repair of tetralogy of Fallot.

A 5-year-old boy with stenosed left pulmonary artery following total correction of tetralogy of Fallot underwent surgical pulmonary arterioplasty through a left anterolateral thoracotomy on a normothermic perfused heart under cardiopulmonary bypass. We found this to be a convenient approach, and recommend it for correction of this lesion in the absence of gross pulmonary regurgitation and right ventricular outflow tract dilatation.

Journal Article↗